Plant-derived pyrrolizidine alkaloid protects eggs of a moth (Utetheisa ornatrix) against a parasitoid wasp (Trichogramma ostriniae).

Pyrrolizidine alkaloid (PA), sequestered by the moth Utetheisa ornatrix from its larval food plant, is transmitted by both males and females to the eggs. Males confer PA on the female by seminal infusion, and females pass this gift, together with PA that they themselves procured as larvae, to the eggs. Here we show that PA protects the eggs against parasitization by the chalcidoid wasp, Trichogramma ostriniae.